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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 15 Apr 2022.
JunosOperating system · Juniper

CVE-2020-1631

CRITICAL · 9.8 CVSS v3.1 Published 2020-05-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
In the wild Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP) allows an unauthenticated attacker to perform local file inclusion (LFI) or path traversal. Using this vulnerability, an attacker may be able to inject commands into the httpd.log, read files with 'world' readable permission file or obtain J-Web session tokens. In the case of command injection, as the HTTP service runs as user 'nobody', the impact of this command injection is limited. (CVSS score 5.3, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) In the case of reading files with 'world' readable permission, in Junos OS 19.3R1 and above, the unauthenticated attacker would be able to read the configuration file. (CVSS score 5.9, vector CVSS:3.1/ AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N) If J-Web is enabled, the attacker could gain the same level of access of anyone actively logged into J-Web. If an administrator is logged in, the attacker could gain administrator access to J-Web. (CVSS score 8.8, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled. Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf To summarize: If HTTP/HTTPS services are disabled, there is no impact from this vulnerability. If HTTP/HTTPS services are enabled and J-Web is not in use, this vulnerability has a CVSS score of 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N). If J-Web is enabled, this vulnerability has a CVSS score of 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Juniper SIRT has received a single report of this vulnerability being exploited in the wild. Out of an abundance of caution, we are notifying customers so they can take appropriate actions. Indicators of Compromise: The /var/log/httpd.log may have indicators that commands have injected or files being accessed. The device administrator can look for these indicators by searching for the string patterns "=*;*&" or "*%3b*&" in /var/log/httpd.log, using the following command: user@device> show log httpd.log | match "=*;*&|=*%3b*&" If this command returns any output, it might be an indication of malicious attempts or simply scanning activities. Rotated logs should also be reviewed, using the following command: user@device> show log httpd.log.0.gz | match "=*;*&|=*%3b*&" user@device> show log httpd.log.1.gz | match "=*;*&|=*%3b*&" Note that a skilled attacker would likely remove these entries from the local log file, thus effectively eliminating any reliable signature that the device had been attacked. This issue affects Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S16; 12.3X48 versions prior to 12.3X48-D101, 12.3X48-D105; 14.1X53 versions prior to 14.1X53-D54; 15.1 versions prior to 15.1R7-S7; 15.1X49 versions prior to 15.1X49-D211, 15.1X49-D220; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S8; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S4; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R3-S2 ; 18.4 version 18.4R2 and later versions; 19.1 versions prior to 19.1R1-S5, 19.1R3-S1; 19.1 version 19.1R2 and later versions; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2; 20.1 versions prior to 20.1R1-S1, 20.1R2.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Unauthenticated local file inclusion (LFI) and path traversal vulnerability in Juniper Junos OS HTTP/HTTPS services (J-Web, Web Auth, DVPN, ZTP) allows attackers to inject commands into httpd.log, read world-readable files including configuration, or obtain active J-Web session tokens. The httpd service runs as 'nobody' user, limiting command injection impact but enabling full J-Web access if administrator is logged in.

MitigationDisable HTTP/HTTPS services if not required, or apply vendor patches for affected versions; review /var/log/httpd.log and rotated logs for patterns '=*;*&' or '=*%3b*&' as indicators of compromise.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:= 12.3= 12.3x48= 14.1x53= 15.1= 15.1x49= 16.1= 17.2= 17.3= 17.4= 18.1= 18.2= 18.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify if J-Web is enabled
    Run 'show system services web-management' or check configuration under 'system services web-management'
    Affected if J-Web is enabled (this is required for the vulnerability to be exploitable)
  2. Check installed Junos OS version
    Run 'show version' or 'show version brief' and compare the numeric version to the affected list: 12.3, 12.3X48, 14.1X53, 15.1, 15.1X49, 16.1, 17.2, 17.3, 17.4, 18.1, 18.2, 18.3
    Affected if Installed version matches one of the listed affected versions
  3. Confirm HTTP/HTTPS services are listening
    Run 'show system services web-management http' or check netstat/ss for ports 80/443 listening on management interface
    Affected if HTTP or HTTPS services are active and listening
  4. Inspect httpd.log for compromise indicators
    Examine /var/log/httpd.log (and rotated logs) for suspicious patterns such as '=*;*&' or URL-encoded equivalents '%3b' indicating command injection attempts
    Affected if Log contains suspicious patterns suggesting exploitation attempts

You are affected if J-Web is enabled, HTTP/HTTPS services are listening, AND your Junos version is in the affected list, regardless of whether exploitation signs appear in logs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Disable HTTP/HTTPS services if not required, or apply vendor patches for affected versions; review /var/log/httpd.log and rotated logs for patterns '=*;*&' or '=*%3b*&' as indicators of compromise.

Recommended fix High confidence

Version-specific fixed releases (12.3R12-S16, 12.3X48-D105, 14.1X53-D54, 15.1R7-S7, 15.1X49-D220, 16.1R7-S8, 17.2R3-S4, 17.3R3-S8, 17.4R3-S2, 18.1R3-S10, 18.2R3-S4, 18.3R3-S2, 18.4R3-S2, 19.1R3-S1, 19.2R2, 19.3R3, 19.4R2, 20.1R2 or later)

  1. 1. Verify HTTP/HTTPS services are enabled on the device by running: show system processes | match http
  2. 2. If HTTP/HTTPS services are not required, disable them to eliminate the attack surface entirely using the configuration: delete system services web-management http or delete system services web-management https
  3. 3. If HTTP/HTTPS services are required, identify the current Junos OS version using: show version
  4. 4. Upgrade to a fixed release for your version branch as follows: 12.3 → 12.3R12-S16, 12.3X48 → 12.3X48-D105, 14.1X53 → 14.1X53-D54, 15.1 → 15.1R7-S7, 15.1X49 → 15.1X49-D220, 16.1 → 16.1R7-S8, 17.2 → 17.2R3-S4, 17.3 → 17.3R3-S8, 17.4 → 17.4R3-S2, 18.1 → 18.1R3-S10, 18.2 → 18.2R3-S4, 18.3 → 18.3R3-S2, 18.4 → 18.4R3-S2, 19.1 → 19.1R3-S1, 19.2 → 19.2R2, 19.3 → 19.3R3, 19.4 → 19.4R2, 20.1 → 20.1R2
  5. 5. After upgrade, verify the fix by checking that httpd processes are running the patched version
  6. 6. Review /var/log/httpd.log for indicators of compromise using: show log httpd.log | match "=*;*&|=*%3b*&"
  7. 7. Also check rotated logs: show log httpd.log.0.gz | match "=*;*&|=*%3b*&" and show log httpd.log.1.gz | match "=*;*&|=*%3b*&"
  8. 8. Consider resetting credentials and reviewing administrator sessions if compromise is suspected
Caveat Standard Junos upgrade considerations apply - review release notes for compatibility, test in lab environment before production deployment, and plan maintenance window

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Exploited in the wild — priority engagement
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  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-1631 in production — separate from our analysis above.

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